Caltech faint galaxy redshift survey. XIV. Galaxy morphology in the Hubble Deep Field (North) and its flanking fields to z = 1.2

Sidney Van Den Bergh, Judith G. Cohen, David W. Hogg, Roger Blandford

    Research output: Contribution to journalReview article

    Abstract

    Morphological classifications are reported for Hubble Space Telescope images of 241 galaxies in the Hubble Deep Field and its flanking fields with measured redshifts in the interval 0.25 < z < 1.2, drawn from a magnitude-limited redshift survey to R = 24.0. The galaxies are divided into three groups with redshifts in the intervals 0.25-0.6, 0.6-0.8, and 0.8-1.2. R606 images from the first group and I814 images from the second and third groups are compared with B-band images of nearby galaxies. All classifications were therefore made at approximately the same rest wavelength. Selection biases are discussed. We corroborate and extend the results of earlier investigations by observing that 1. Most intermediate- and late-type galaxies with z ≳ 0.5 have morphologies that are dramatically different from those of local galaxies and cannot be shoehorned into the Hubble "tuning fork" classification scheme; 2. Grand-design spirals appear to be rare or absent for z ≳; 0.3; 3. Many Sa and Sb spirals with z ≳ 0.6 do not exhibit well-defined spiral arms, and the arms of distant Sc galaxies appear more chaotic than those of their nearby counterparts; 4. The fraction of all galaxies that are of types Sc and Scd drops from 23% at z ∼ 0 to 5% for z > 0.6. 5. Barred spirals are extremely rare for z ≳ 0.5; 6. Roughly one in five galaxies with z ∼ 0.8 is a compact objects that resembles local E, S0, or Sa galaxies. 7. Peculiar galaxies are more common beyond z = 0.3, especially among late-type spirals, than they are at z ∼ 0; 8. Merging galaxies, particularly those with three or more components, also become more common with increasing redshift. On the basis of these and similar observations, it is inferred that the development of pronounced spiral structure was delayed until ∼5 Gyr and that most bulges are probably not formed by disintegrating bars. Major morphological changes were still taking place only ∼5 Gyr ago, even though changes in the integrated light of most galaxies were then much slower than they were ∼10 Gyr ago.

    Original languageEnglish (US)
    Pages (from-to)2190-2205
    Number of pages16
    JournalAstronomical Journal
    Volume120
    Issue number5
    DOIs
    StatePublished - Nov 2000

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    Keywords

    • Galaxies: evolution
    • Surveys

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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